In summary, we have developed a technique for site-specific nanowire size reduction by FIB thinning. Transmission electron microscope images of a thinned tungsten composite nanowire with width reduced from 80 to 20nm show uniform shrinking along the length of the wire and high resolution images show no obvious changes of the morphology after thinning. The critical current density of the as-deposited wire and one thinned to a width of 50nm is 1.7×105 and 1.4×105A/cm2 at 4.26K, respectively, suggesting insignificant modulation of the electrical properties during thinning. These results suggest that FIB-milling is a potential approach for controllable size reduction with high resolution towards the observation of size- and quantum effects, as well as for construction of 3D superconducting nanodevices.
